Positive and negative regulation by thyrotropin of thyroid cyclic AMP response to thyrotropin in porcine thyroid cells

Takasu, Nobuyuki; Charrier, Bernard; Mauchamp, Jean; Lissitzky, Serge

doi:10.1016/0014-5793(77)81087-9

Cited by 23 publications

(11 citation statements)

References 7 publications

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“…However, the increased responsiveness, demonstrated in the present study, has been reported in vasopressin sensitive adenylate cyclase from the kidney of rats (Rajerison et al 1977), and cyclic AMP formation stimulated by thyrotrophin in the thyroid cells (Takasu et al 1977). Our observation that the amount of corticosterone secreted during the first half hour following the ACTH injection was sig¬ nificantly larger after the second injection than after the first one, seems to be similar to the priming effect of URH on the pituitary (Aiyer et al 1973;Fink et al 1975).…”

Section: Discussionsupporting

confidence: 85%

Enhancement of corticosterone release by repeated injections of ACTH in the dexamethasone pre-treated rat

Murakami

Takahashi

1983

Acta Endocrinologica

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To examine the possibility that pulsatile secretion of adrenocorticotrophic hormone (ACTH) enhances the responsiveness of the adrenal, the blood corticosterone response to repeated injections of ACTH was determined in the dexamethasone-nembutal pre-treated rat. Treatment with dexamethasone (100 \g=m\g/100g body weight) at 13.00 h for 2 days decreased corticosterone levels and completely abolished these daily variations in both the blood and adrenal. Under these conditions, four or five successive iv injections of 0.2 or 2 mIU ACTH were given at \ m=1/ 2\or 1 h intervals. Blood samples were taken immediately before and at frequent intervals after injection. A significant increase of blood corticosterone levels was observed 10 min after the second injection of 0.2 mIU ACTH. Further increases in blood corticosterone levels were observed after the subsequent injections. In addition, repeated injections of 2 mIU ACTH augmented the responsiveness of the adrenal to ACTH. The second or the third injections of 2 mIU ACTH produced a greater increase in adrenal corticosterone content than did the first ACTH injection.These results suggest that when ACTH acts on the adrenal gland in a pulsatile fashion, the steroidogenic response of the adrenal to ACTH increases markedly.

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Section: Discussionsupporting

confidence: 85%

Enhancement of corticosterone release by repeated injections of ACTH in the dexamethasone pre-treated rat

Murakami

Takahashi

1983

Acta Endocrinologica

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“…Indeed, in mice experiments in vivo Gafni et al [8] observed that the prolonged absence of an adequate level of thyrotropin may be responsible for thyroidal unresponsiveness to acute thyrotropin treatment. In another system, Rajerison et al [9] showed that blood vasopressin levels in rat exert a dual regulation on renal adenylate cyclase responsiveness to vasopressin stimulation. Positive regulation was operating in the range of physiological levels whereas negative regulation could only be demonstrated at pharmacological blood vasopressin levels.…”

Section: Discussionmentioning

confidence: 99%

Modulation of Adenylate Cyclase/Cyclic AMP Response by Thyrotropin and Prostaglandin E2 in Cultured Thyroid Cells. 2. Positive Regulation

et al. 1978

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Two different independent processes are operating in cultured thyroid cells to regulate adenylate cyclase/cyclic AMP responsiveness to thyroid stimulators (thyrotropin and prostaglandin Ez) :firstly, refractoriness or negative regulation [preceding paper], which is specific for each thyroid stimulator, is not mediated by cyclic AMP and is not accompanied by alteration of adenylate cyclase activity; secondly, positive regulation which is characterized by an augmentation of the cyclic AMP response stimulated by thyrotropin and prostaglandin E2. This process is not specific for each thyroid stimulator and is a state of increased susceptibility of cyclic AMP synthesis to stimulation, accompanied by increased activity of the catalytic subunit of adenylate cyclase. Positive regulation is apparently mediated by increased intracellular cyclic AMP levels. It is a time-dependent and dose-dependent process. Very low concentrations ( 5 -50 pU/ml) of thyrotropin augmented cyclic AMP synthesis stimulated by thyrotropin and prostaglandin E2 whereas higher concentrations (above 0.1 mU/ml) augmented prostaglandin El stimulation but induced refractoriness to thyrotropin. Prostaglandin E2 (0.1 to 10 pM) augmented thyrotropin stimulation and dibutyryl adenosine 3' : 5'-monophosphate (0.3 to 2 mM) augmented thyrotropin and prostaglandin Ez stimulation. Positive regulation is a slow process which develops within days and increases up to day 5 in culture. Experiments using inhibitors suggested that protein synthesis is required for the full expression of the increase in adenylate cyclase activity induced by the studied thyroid stimulators.We have recently shown that the cyclic AMP response to thyrotropin of thyroid cells in culture was under a dual regulation by thyrotropin : chronic exposure of the cells to physiological concentrations of the hormone augmented the subsequent cyclic AMP response to thyrotropin (positive regulation), whereas moderate to high concentrations of thyrotropin induced refractoriness to further thyrotropin stimulation [l].The conditions for the development of refractoriness to thyrotropin and prostaglandin Ez have been described in a preceding paper [2]. In this report, we analyze the mechanism of the positive regulation of the acute cyclic AMP response to thyrotropin and prostaglandin E2 as influenced by chronic treatment of cultured thyroid cells with these stimulators. MATERIALS AND METHODSThe methods and the materials used have been described in the preceding paper [ 2 ] . Cells cultured in the presence of thyrotropin (10 mU/ml), prostaglandin EZ (1 pM) or dibutyryl cyclic AMP (0.4 mM) will be referred to further as thyrotropin-treated, prostaglandin E2-treated or BtzcAMP-treated cells, respectively. Cells cultured in the absence of these compounds will be referred to as control cells.Cyclic AMP synthesis using prelabeling technique with 14C-labeled adenine [3] was measured as reported previously [4] with minor modifications. Duration of preincubation with [14C]adenine was 40 rnin. To preserve cell viab...

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“…The Eagle minimum essential medium used was buffered at pH 7.4 and supplemented with 10% newborn calf serum and contained 200 units/ml penicillin, 50 pU/ml streptomycine sulfate and 0.25% (w/v) gelatin [8]. Freshly isolated cells (10 ml) were incubated at 2 X lo6 cells/ml in polystyrene Petri dishes not treated for tissue culture to avoid cell attachment to the support and spreading.…”

Section: Cell Isolation and Culturementioning

confidence: 99%

Modulation of adenylate cyclase activity by thyrotropin in cultured thyroid cells

et al. 1980

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Positive and negative regulation by thyrotropin of thyroid cyclic AMP response to thyrotropin in porcine thyroid cells

Cited by 23 publications

References 7 publications

Enhancement of corticosterone release by repeated injections of ACTH in the dexamethasone pre-treated rat

Enhancement of corticosterone release by repeated injections of ACTH in the dexamethasone pre-treated rat

Modulation of Adenylate Cyclase/Cyclic AMP Response by Thyrotropin and Prostaglandin E2 in Cultured Thyroid Cells. 2. Positive Regulation

Modulation of adenylate cyclase activity by thyrotropin in cultured thyroid cells

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